The use of liquid crystal based materials in lighting applications is known in the art. WO2010035171, for instance, describes a lighting device comprising a light source arranged to generate light source light, an optional luminescent material, and a thermally variable reflecting element. The optional luminescent material is arranged downstream of the light source and is arranged to convert at least part of the light source light into luminescent material light. One or more of the light source and the optional luminescent material generate heat when the light source generates light source light. The thermally variable reflecting element is arranged downstream of the light source and the optional luminescent material. The thermally variable reflecting element has a first state wherein it is substantially reflecting and a second state wherein it is substantially transparent; heat induces a chance from the first state to the second state. The thermally variable reflecting element is arranged to transmit at least part of one or more selected from the group consisting of the light source light and optional luminescent material light when being in the second state. The lighting device is arranged to transport heat generated by one or more of the light source and the optional luminescent material to the thermally variable reflecting element.
JP2010027586 describes a liquid crystal dimming shutter or a high polymer distributed liquid crystal dimming shutter that is arranged in front of the light emitting diode. Preferably, illumination of the diffused light, the dimmed light and also a desired light color is provided by adding or dispersing a predetermined phosphor or a pigment in the liquid crystal dimming shutter. The shutter comprises an electrically activated liquid crystal material.
US2011/0176076 describes a lighting device comprising a light source arranged to generate light source light, an optional luminescent material and a thermally variable reflecting element. The optional luminescent material is arranged downstream of the light source and is arranged to convert at least part of the light source light into luminescent material light. One or more of the light source and the optional luminescent material generate heat when the light source generates light source light. The thermally variable reflecting element is arranged downstream of the light source and the optional luminescent material. The thermally variable reflecting element has a first state wherein it is substantially reflecting and a second state wherein it is substantially transparent; heat induces a chance from the first state to the second state. The thermally variable reflecting element is arranged to transmit at least part of one or more selected from the group consisting of the light source light and optional luminescent material light when being in the second state. The lighting device is arranged to transport heat generated by one or more of the light source and the optional luminescent material to the thermally variable reflecting element.
US2012/018754 describes a light emitter device, package, or lamp that comprises and light emitter and a light transmission control material to mask the appearance of at least the light emitter. In one embodiment, a light emitting diode (LED) based lamp is disclosed, comprising an LED light source. A phosphor is arranged remote to the light source such that light emitted from the light source passes through this phosphor and is converted by this phosphor. A light transmission control material is applied at least partially outside the LED light source and the phosphor to reversibly mask the appearance of the LED light source and the phosphor. The light transmission control material is less masking when the LED light source is active. A method for masking the appearance of inactive light emitters is also disclosed that comprising providing at least one light emitter. Each of the at least one light emitters is provided with a light transmission control material over the light emitters to reversibly mask the appearance of the light emitters while the light emitters are inactive. The light transmission control material is less masking when the LED light source is active.